Underwood 220gr Hard Cast Flat Nose

[REDLINE]

I'm thinking Double Tap simply doesn't have any form of Quality Control whatsoever.  I have yet to come across a single sign that they do, other than that when I have bought ammo from them in the past it somehow it turned out all the brass was 10mm Auto.  I guess they had to start somewhere.  The problem is it seems to be that's where it ended.  Maybe Double Tap's Quality Control is to have no Quality Control?

[MrRedbull616]

I called Rimrock  - they said the 220 is from their Premium line and is a much harder cast thus there isn't a need for a gas check.

I guess I could agree with that shooting the 220 into some phone books - I see nothing going on with the base of the bullet to make me suspect it's getting burned at the bottom etc

[DM1906]

I use a similar method to drive the big magnums (10mm and up) at warp speed.  Alloy, hardness, correct bullet diameter (slug the barrel to confirm!), powder selection, lube selection, plus I add a coating of lube on the bullet base.  If you aren't seeing any leading, and the bullet base isn't pitting, a gas check isn't needed.

[Yondering]

It's not the flat base of the bullet that you need to be looking at. Look closely at the back edge of the rear driving band, at the end of the rifling marks; look for flame cutting. I've never recovered a plain base cast bullet pushed to magnum velocity that doesn't have flame cutting around the base.

[harrygunner]

Ordered a few boxes of the Underwood 220gr hard cast. And will be picking up a chronograph.

Figured I'd place targets at fifty yards and slow-fire 180gr and 220gr ammo from a rest, over the chronograph.

I can then, compare group sizes. If the 220gr groups are reasonably similar to the 180gr groups, then that should confirm they stabilize.

[REDLINE]

That would definitely confirm, or not, stabilization.  I don't know if twist rates vary between different 10mm Auto platforms or not, but that could show a more favorable outcome one way or another.  And more barrel length to up velocity might favorably increase stabilization, like between a G20 4.6" and a G20 accessory 6.02".

At any rate, your results will truly shed light one way or the other.  I'll be looking forward to your results.

[Bronco]

Ordered a few boxes of the Underwood 220gr hard cast. And will be picking up a chronograph.

Figured I'd place targets at fifty yards and slow-fire 180gr and 220gr ammo from a rest, over the chronograph.

I can then, compare group sizes. If the 220gr groups are reasonably similar to the 180gr groups, then that should confirm they stabilize.

I uncovered this thread while searching for info on possible lower 48 bear defense loads and was wondering if you'd ever had a chance to conduct your 50 yard stabilization testing. 

[harrygunner]

I did test stability of Underwood's 220gr hardcast. Changed the test a bit. I compared groups between the Glock 29 and a 1911 with a Bar-Sto barrel.

Posted my results here: http://10mm-firearms.com/factory-10mm-ammo/underwood-220gr-hc/15/

In my opinion, the UW hardcast bullets are softer, with a slightly larger diameter that allowed them to stabilize in the Glock.

[Bronco]

I did test stability of Underwood's 220gr hardcast. Changed the test a bit. I compared groups between the Glock 29 and a 1911 with a Bar-Sto barrel.

Posted my results here: http://10mm-firearms.com/factory-10mm-ammo/underwood-220gr-hc/15/

In my opinion, the UW hardcast bullets are softer, with a slightly larger diameter that allowed them to stabilize in the Glock.

Thanks much for the quick response, harry.  Off now to check out the other thread.